Innovations in gas turbines to be pursued In 2 new energy department projects
With the natural gas turbine fast becoming the workhorse for new power generating plants in the United States, the U.S. Department of Energy is preparing to award two new research contracts that could help improve the environmental performance and efficiencies of tomorrow's high-efficiency turbines.
As part of a wide-ranging competition, the Department's National Energy Technology Laboratory has selected General Electric Co., Niskayuna, NY, for projects to develop a new gas turbine combustion system and a "Smart Power Turbine" sensor-and control system.
A Cleaner Burning Combustor:
In the combustion system research, GE engineers hope to develop a prototype combustor that will reduce smog-causing nitrogen oxide emissions well below current systems.
The goal is to cut emissions by 50 percent or more compared to state-of-the-art lean premixed gas turbine combustors.
Currently GE's dry low-NOx (DLN) combustion technology, which the company pioneered in the early 1990s, has been installed on more than 250 gas turbines.
The most advanced DLN designs reduce nitrogen oxide emissions to less than 10 parts per million (on a dry, 15percent oxygen basis).
As next-generation turbine power plants evolve, the gas turbines will be required to operate at higher pressure ratios and hotter turbine inlet temperatures – conditions that will tend to increase nitrogen oxide emissions.
To conform to future air quality requirements, lower-emitting combustion technology will be required.
GE researchers will evaluate several combustor concepts at small scales and use them to refine computer models and generate a design database.
From this data, prototype combustors, employing new designs, will be built and evaluated over a variety of conditions. The best design will be selected for full-scale design evaluation.
The Energy Department will supply $1.14 million with GE proposing to contribute $760,000 to the 31 month effort.
A "Smart Power Turbine":
Improving sensors and control systems could be a way to boost future turbine efficiencies.
For example, today's turbines control firing temperatures indirectly – by measuring the exhaust gas temperature and the heating value of the fuel, then mathematically calculating the peak combustor temperatures.
But temperatures in a turbine's hot gas path can vary by as much as 100 degrees F, making it difficult to control firing temperatures precisely enough to achieve peak efficiencies.
Similarly, there is no current way to assess wear of turbine components within the hot gas path in real time, without shutting down the turbine.
Consequently, maintenance and component replacements are often scheduled on conservative design practices based on historical data.
The new Energy Department project is intended to help resolve both problems by developing a suite of novel senors that would measure combustor flame temperature and hot-gas-path component life directly.
The sensors and controls would be applicable to both new and existing turbines.
By enabling turbines to operate much closer to their design limits, it may be possible to significantly increase the marginal capacity of gas turbine systems – meaning cost savings for the power industry and more electric power for the nation's consumers.
For this 2-year project, the Energy Department proposes to provide $1.1 million, an amount that GE proposes to match.
The Department's involvement in both development efforts will be coordinated through its fossil energy program and managed by the National Energy Technology Laboratory at Morgantown, WV, and Pittsburgh, PA.
Source:United States Energy Information Administration
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